Bacterial Symbiosis

[Garf]

Looks as though the growth of algae could be very dependant upon the particular bacterial strains that populate the screen. If correct, perhaps adding a bit of live rock, sand, algae etc to the tank (from a new source) may improve screens that are suffering from wierd growth.

http://www.mendeley.com/research/isolation-seaweed-associated-bacteria-morphogenesis-inducing-capability-axenic-cultures-green-alga-u/

[Clavius]

I add Zeobak to my system two times a week. (Paracoccus Denitrificans.) And the screen on my three month old scrubber has always been freakishly bright yellow. Then could those bacteria be the reason my scrubber never turned green?

[SantaMonica]

No, the reason would be too little N and P delivered to the screen, compared to how much light there is.

More bubbles, more water holes, more distance from the light, and/or less hours will fix it.

[Garf]

Algae contains vitamin B12, algae cannot produce B12, the only organisms that can produce B12 are bacteria.